fix: staking legacy contract call when slashing

Author: Maikol

src/mappings/staking.ts

@@ -161,21 +161,41 @@ export function handleStakeSlashed(event: StakeSlashed): void {
   let id = event.params.indexer.toHexString()
   let indexer = Indexer.load(id)!
 
-  indexer.stakedTokens = indexer.stakedTokens.minus(event.params.tokens)
+  let slashedTokens = event.params.tokens
+
+  // When tokens are slashed, locked tokens might need to be unlocked if indexer overallocated
+  if (slashedTokens.gt(BigInt.fromI32(0))) {
+    let tokensUsed = indexer.allocatedTokens.plus(indexer.legacyLockedTokens)
+    let tokensAvailable = tokensUsed.gt(indexer.stakedTokens)
+      ? BigInt.fromI32(0)
+      : indexer.stakedTokens.minus(tokensUsed)
+
+    if (slashedTokens.gt(tokensAvailable) && indexer.legacyLockedTokens.gt(BigInt.fromI32(0))) {
+      let tokensOverAllocated = slashedTokens.minus(tokensAvailable)
+      // Calculate min(tokensOverAllocated, lockedTokens)
+      let tokensToUnlock = tokensOverAllocated.lt(indexer.legacyLockedTokens)
+        ? tokensOverAllocated
+        : indexer.legacyLockedTokens
+
+      indexer.legacyLockedTokens = indexer.legacyLockedTokens.minus(tokensToUnlock)
+      indexer.lockedTokens = indexer.lockedTokens.minus(tokensToUnlock)
+
+      if (indexer.legacyLockedTokens.equals(BigInt.fromI32(0))) {
+        indexer.legacyTokensLockedUntil = 0
+        indexer.tokensLockedUntil = 0
+      }
+    }
+  }
+
+  // Now reduce the staked tokens (this happens at the end in the contract)
+  indexer.stakedTokens = indexer.stakedTokens.minus(slashedTokens)
 
-  // We need to call into stakes mapping, because locked tokens might have been
-  // decremented, and this is not released in the event
-  // To fix this we would need to indicate in the event how many locked tokens were released
-  let staking = Staking.bind(event.address)
-  let indexerStored = staking.stakes(event.params.indexer)
-  indexer.lockedTokens = indexerStored.tokensLocked
-  indexer.legacyLockedTokens = indexerStored.tokensLocked
   indexer = updateLegacyAdvancedIndexerMetrics(indexer as Indexer)
   indexer = calculateCapacities(indexer as Indexer)
   indexer.save()
 
   // Update graph network
-  graphNetwork.totalTokensStaked = graphNetwork.totalTokensStaked.minus(event.params.tokens)
+  graphNetwork.totalTokensStaked = graphNetwork.totalTokensStaked.minus(slashedTokens)
   graphNetwork.save()
 }